package com.hq.hotl.utils;




import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

    /**
     * 验证码生成类
     * Created by zhm on 2017/9/30.
     */
    public class RandomValidateCode {
        public static final String RANDOMCODEKEY= "RANDOMVALIDATECODEKEY";//放到session中的key
        //private String randString = "0123456789";//随机产生只有数字的字符串 private String
        private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生只有字母的字符串
        //private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生数字与字母组合的字符串
        private int width = 95;// 图片宽
        private int height = 25;// 图片高
        private int lineSize = 40;// 干扰线数量
        private int stringNum = 4;// 随机产生字符数量

        private Random random = new Random();

        /*
         * 获得字体
         */
        private Font getFont() {
            return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
        }

        /*
         * 获得颜色
         */
        private Color getRandColor(int fc, int bc) {
            if (fc > 255)
                fc = 255;
            if (bc > 255)
                bc = 255;
            int r = fc + random.nextInt(bc - fc - 16);
            int g = fc + random.nextInt(bc - fc - 14);
            int b = fc + random.nextInt(bc - fc - 18);
            return new Color(r, g, b);
        }

        /**
         * 生成随机图片
         */
        public void getRandcode(HttpServletRequest request, HttpServletResponse response) {
            HttpSession session = request.getSession();
            // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
            BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
            Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
            g.fillRect(0, 0, width, height);
            g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
            g.setColor(getRandColor(110, 133));
            // 绘制干扰线
            for (int i = 0; i <= lineSize; i++) {
                drowLine(g);
            }
            // 绘制随机字符
            String randomString = "";
            for (int i = 1; i <= stringNum; i++) {
                randomString = drowString(g, randomString, i);
            }
            //将生成的随机字符串保存到session中，而jsp界面通过session.getAttribute("RANDOMCODEKEY")，
            //获得生成的验证码，然后跟用户输入的进行比较
            session.removeAttribute(RANDOMCODEKEY);
            session.setAttribute(RANDOMCODEKEY, randomString);
            g.dispose();
            try {
                // 将内存中的图片通过流动形式输出到客户端
                ImageIO.write(image, "JPEG", response.getOutputStream());
            } catch (Exception e) {
                e.printStackTrace();
            }

        }

        /*
         * 绘制字符串
         */
        private String drowString(Graphics g, String randomString, int i) {
            g.setFont(getFont());
            g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
                    .nextInt(121)));
            String rand = String.valueOf(getRandomString(random.nextInt(randString
                    .length())));
            randomString += rand;
            g.translate(random.nextInt(3), random.nextInt(3));
            g.drawString(rand, 13 * i, 16);
            return randomString;
        }

        /*
         * 绘制干扰线
         */
        private void drowLine(Graphics g) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(13);
            int yl = random.nextInt(15);
            g.drawLine(x, y, x + xl, y + yl);
        }

        /*
         * 获取随机的字符
         */
        public String getRandomString(int num) {
            return String.valueOf(randString.charAt(num));
        }
    }

